1. Field of the Invention
The present invention relates to a system and method for disk drive grouping in a multi-cell disk drive test system used to test disk drives.
2. Description of the Prior Art and Related Information
FIG. 1 shows the principal components of an example of a magnetic disk drive 100 that may be tested in a multi-cell disk drive testing system. With reference to FIG. 1, the disk drive 100 comprises a head disk assembly (HDA) 144 and a printed circuit board assembly (PCBA) 114. The HDA 144 includes a disk drive enclosure comprising a base 116 and a cover 117 attached to the base 116 that collectively house a disk stack 123 that includes one or a plurality of magnetic disks (of which only a first disk 111 and a second disk 112 are shown), a spindle motor 113 attached to the base 116 for rotating the disk stack 123, an HSA 120, and a pivot bearing cartridge 184 that rotatably supports the head stack assembly (HSA) 120 on the base 116. The spindle motor 113 rotates the disk stack 123 at a constant angular velocity.
The HSA 120 comprises a swing-type or rotary actuator assembly 130, at least one head gimbal assembly (HGA) 110, and a flex circuit cable assembly 180. The rotary actuator assembly 130 includes a body portion 140, at least one actuator arm 160 cantilevered from the body portion 140, and a coil portion 150 cantilevered from the body portion 140 in an opposite direction from the actuator arm 160. The actuator arm 160 supports the HGA 110 that, in turn, supports the slider(s). The flex cable assembly 180 may include a flex circuit cable and a flex clamp 159.
The HSA 120 is pivotally secured to the base 116 via the pivot-bearing cartridge 184 so that the slider at the distal end of the HGA 110 may be moved over the surfaces of the disks 111, 112. The pivot-bearing cartridge 184 enables the HSA 120 to pivot about a pivot axis, shown in FIG. 1 at reference numeral 182. The storage capacity of the HDA 144 may be increased by, for example, increasing the track density (the TPI) on the disks 111, 112 and/or by including additional disks in the disk stack 123 and by an HSA 120 having a vertical stack of HGAs 110 supported by multiple actuator arms 160.
The “rotary” or “swing-type” actuator assembly comprises body portion 140 that rotates on the pivot bearing 184 cartridge between limited positions, coil portion 150 that extends from one side of the body portion 140 to interact with one or more permanent magnets 192 mounted to back irons 170, 172 to form the voice coil motor (VCM), and the actuator arm 160 that supports the HGA 110. The VCM causes the HSA 120 to pivot about the actuator pivot axis 182 to cause the slider and the read write transducers thereof to sweep radially over the disk(s) 111, 112.
After the HDA 144 and the PCBA 114 are mated, the disk drive typically undergoes a variety of tests and procedures to configure and validate the proper operation of the disk drive. Such testing is conventionally carried out in a multi-cell disk drive test platform that includes a bank of cells into which the disk drives are loaded and unloaded such that a sequential series of tests and procedures can be administered to the loaded disk drives. Some of the tests and procedures are subject to strict environmental control requirements.
Because disk drive testers and disk drive testing represent such large expenditures for disk drive manufacturers, more efficient testers and testing procedures are continuously sought after in order to reduce inefficiencies and costs and to increase disk drive throughput. One particular source of inefficiency associated with conventional multi-cell disk drive test systems is that multiple cells are often tested together and disk drives with different characteristics in these cells may take differing amounts of time to complete the tests. Thus, the throughput of these multiple cells is limited to the time it takes the slowest disk drive to complete the testing.